Process of making electrodes for secondary batteries.



J. APOZNANSKI. PROCESS 0I' MAKING ELEGTRODBS FOR SECONDARY BATTERIES. APPLICATION PILEP DEG. 14, 1910. 1,1 14,667, Patented 0015.20, 1914.

JOSEPH A POZNAN SKI, F MOSCOW,

BUssIA, AssIGNon To THE FIRM 0F STANISLAW &

GEORG-IJ' GASZ'YNSKI BROS., APOZNANSKI & CO., 0F MOSCOW, RUSSIA.

Pnocnss or 'MAKING ELEcTRonns Fon sEcoNnAnY BATTERIES.

' Specification of Letters Patent. Application led December 14, 1910. Serial No.

Patentedct. 20, 1914. 597,375.

To all whom it may concern Be it known that I, JOSEPH APozNANsKr, a subject of the Czar of Russia, residing in Moscow, in the Empire of Russia, have invented certain new and useful Improvements in Processes of Making Electrodes for Secondary Batteries, of which the following is a specification.

My im-'ention relates to the manufacture of electrodes for secondary batteries, and a primary object is to provide an exceedingly simple process, by Which not only an exceptionally large effective capacity of the electrodes is obtained. but simultaneously, besides a great porosity of the same, and considerable durability, even When they are 'severel discharged. y e

My process is carried into practice as follows: My process is carried out by the aid of apparatus which is shown in the accompanying drawings, in 'which- Figure l is a vertical longitudinal section showing the oven with banks of plates therein, Fig. 2 is a Vertical transverse section on. line 2--2 of Fig. 1, and Fig. 3 is a detail view o-f the arrangement of the plates, grids, paste, etc., While being subjected-to the heating process.

In these figures, similar characters of reference indicate corresponding parts, and in which the oven is provided With doors ll and l2 at the front thereof, and a grate 13 at the lower portion thereof, for the support of the fuel. Supported Within the oven l0 is a chamber l5 Which isprovided with several superposed supporting-plates 16, each of which consists of a pluralitybf spaced bars 16, so as to permit the heat to pass between the same. The chamber .l5 is smaller than the oven casing, and is arranged so as to provide vertical channels 20 and 2l at either side of the chamber l5, and a channel 22 abo-ve the same for the passage of the heat produced by the burning of the fuel. After the heat has done its work, it passes out of the chimney 23.

In the chamber 15 and on the support 16 are arranged a plurality of banks, indicated by 25, one .of Which is c-learly'shown in Fig. 3. These banks are built up by arranging alternatelyT glass plates and electrodes 33,- which electrodes are built up b the lead grids 31 and a paste 32. At the ends of the glass plates and electrodes, a

layer of paste is provided so as to cover up any leaks, which layer is indicated by 34, and on the top of the uppermost glass plate, a Weight of lead or any other suitable material arranged so as to hold down the plates in position. Vhen the electrodes are thusarranged in the manner indicated, they are subjected to the heat in the oven, and the process hereinafter described is carried out. The process is carried out by having always the entire banks placed in the oven and not the single plates. It Will be noticed that each one of these banks contains six accumulator plates and seven cover plates. As some gases, as for instance, Water4 vapors, may i'ill the interior of the chamber 15 on the carrying it might sometimes be preferable to have an exhaust )ipe exhaust these gases. For this reason, t e tube 37 is provided, which enables these water vapors to pass into the chimney 23. In Fig. 3, the bank is shown in approximate natural size.

Lead salts, e. g. minium alone or minium mixed with litharge, or merely litharge alone with sulfuric acid and distilled Water, are mixed to form a thick aste, to which subsequentlyis'added some giycerin. The uantity of sulfuric acid which is employed is of special importance and is so selected, in proportion to the quantity of Water, that When diluted sulfuric acid is mixed With minium the color of the latter does not change. `When the paste has been mixed with suitably diluted sulfuric acid a small quantity of sulfuricf acid-is added but only so much that the color of the minium becomes only immaterially darker. Some glycerin may then be added to the paste, whereupon the paste is ready for being filled into the grid-plates. It is to be noted that when the quantity of sulfurie acid is tc-o great when making the paste, the durability of the plates is considerably impaired.

Before the paste is lled into the gridplates, it is Well heated and only after it has attained a suitable temperature, lled hot into the plates. Not only lead-plates but also carbon-plates may be employed as grids. In the present process it is not necessary to press the lled grid-plates as is otherwise frequently thought to be preferable, and consequently the grids can be made particularly light and thin, which materially contributes toivard obtaining a battery of light out of the process,

weight. Immediately after -the hot paste secondary battery is materially diminishedl has been put into the grids, the latter are dried in a special manner, to wit, by placing them between smooth plates which are not attacked by sulfuric acid, such as glass or enameled iron plates, and then drying them in a heated chamber. The object of placing the plates between acid-proofvplates, that 1s t0 say, glass or enameled iron plates, is to prevent the admission of air. 4In the one and in the-other case, the temperature at which the plates are dried must be below the melting point` of the lead-grid and of the lead salts used for forming the paste. When the drying process is thus carried into practice, the plates are dried very rapidly, and electrodes obtained in which the active material is exceedingly hard and simultaneously also exceptionally porous. After being dried, forming can at once take place, to which end sulfuric acid of 16 to 26 degrees Beaum is preferably employed. This same electrolyte is also used for the secondary batteries, but l do not desire to be bound to the density just stated. Any desired suitable strength of current may be employed during the forming operation, but the stronger the current which is employed, the more rapidly are the plates formed.

lNhen lead-grids are employed for making the electrodes, the capacity of such a secondary battery is at least 40 ampere-hours per kilogram of electrode, but when carbongrids are employed, this value rises to 50 and more ampere-hours. it is true that such outputs have been, known heretofore, nevertheless they could be obtained only by specially complicated means and at the expense of the durability of the battery. In contradistinction thereto, as mentioned above, my process of manufacture is particularly simple, the plates in themselves have the appearance of an ordinary electrode and their durability is exceptionally great. The active material as such ossesses, besides great p0- rosity, great har ness andresist'ance, while the lead or carbon-grids, serving less for strengthening the electrodes, but mainly as the conductors ofthe current, can therefore be made exceedingly light, so that the entire in weight. l

The invention consists therefore of the improved ste in the art, as also the improved rocess em odying said step, which consists 1n drying the paste filled in the grids and reventing the gases from free exit from the grids during such drying, such drying being carried out very rapidly and at a temperature higher than that of the paste, as has been hereinbefore described, and as will be pointed out in the appended claims.

l claim:

. 1. That step in the herein described process of making electrodes for secondary batteries, which consists in very rapidly rying the paste filled in the grids, and impeding the exit of the gases within the grids during such drying.

2. The process herein described of making electrodes for secondary batteries, which consists in drying the paste filled in the grids, and preventingA the gases from free exit from the grids during such drying, such drying being carried out Very rapidly and at a temperature higher than that of the paste.

3. The process herein described of making consists in fillino the grids with a pasty mass, and thereafter drying them very rapidly while between plates, whereby the gases formed by the drying are prevented from free exit.

4. The process herein described of-making electrodes for secondary batteries,` which consists in filling the grids with a pasty mass, covering the exposed surfaces of the paste lled in the grids, and drying the paste in the grids while so covered, whereby the gases formed during drying are prevented from free exit at the parts so covered.

ln testimony, that l claim the foregoing as my invention, l have signed my name in presence of two subscribing Witnesses.

JOSEPH APOZNAN SKI.

- Witnesses:

STANrsLAs GAszYNsKI, JEHSCAL BOJAR.

, electrodes for secondary batteries, which 

